Extension built on drainage/loft without permission

Section62

gemma.zhang said:

I meant if there was anything wrong with the drainage that we need to dig it out, then replace the extension like for like. Don’t think would involve building application / control. 

I think the issue is that if there was something seriously wrong with the drainage then the first option likely to be looked at would be diverting the pipe so it is no longer under the building.  The old pipe would be abandoned and the building wouldn't need rebuilding (assuming the drainage defect hadn't affected structural stability etc).

If that wasn't possible and demolition of the building was necessary, then I don't think you would be allowed to rebuild like for like, let alone doing it without BC involvement.

It's a bit of a Catch-22

Really until you know what drainage you are dealing with it is just guesswork what the possible outcomes are.

Slinky

gemma.zhang said:

The loft is small with a window, done nicely with proper staircase, fit enough to be an office but not as a room without building regulation / completion certificate. Any risk of me letting out in future as only an office ( not as a room).

Realistically who is likely to want to rent an 'office' which is the loft room in a private residence?  Where would they have access to toilet and kitchen facilities? It's unlikely you'd be able to get contents insurance for your possessions I would have thought.

Section62

RS2OOO said:

Additionally, a majority of drainage repairs these days are done without a requirement to dig since modern methods allow drains to be re-lined in situ, as long as there's nearby manhole access.

I wouldn't say it was a majority - certainly not on the domestic property scale where digging out a shallow pipe and replacing it with plastic is almost always the cheapest and easiest solution.

No-dig techniques are more suitable for cases where the depth of pipe or 'engineering difficulty' makes digging expensive or impractical.  Or where the structure of the pipe is relatively good and the problem is limited to something like leakage at the joints.

But the key issue is as you say "as long as there's nearby manhole access" - which in cases like the one the OP is looking at the owner has compounded the error of building over the drainage by making the manhole inaccessible.  They have put themselves into a corner by ruling out an easy 'dig' repair, and likely making 'no-dig' unfeasible.

gemma.zhang

thanks everyone for valuable advice.
the house is relatively cheaper comparing to neighbouring properties by would say 25k-50k, it’s difficult to valuate.

We still like it very much, really depends on how much does the drainage/loft worth? 

Might just be issues never going to happen during our ownership and we got a bargain price, or might just be trouble to deal with around the corner, worthy more than 25k-50k.

Worth the risk or not ? 

gemma.zhang

Slinky said:

gemma.zhang said:

The loft is small with a window, done nicely with proper staircase, fit enough to be an office but not as a room without building regulation / completion certificate. Any risk of me letting out in future as only an office ( not as a room).

Realistically who is likely to want to rent an 'office' which is the loft room in a private residence?  Where would they have access to toilet and kitchen facilities? It's unlikely you'd be able to get contents insurance for your possessions I would have thought.

Sorry I meant rent out the whole house with that loft room classified as an office.

Remember read a story here in one of the posts, the landlord let out the house with unofficially converted loft marketed as an office and clearly stated in rental agreement, the tenants still used it as a room, after they got told off by the landlord they reported to the council, and council enforced the landlord to convert the loft properly under building regulation, which left the landlord tens of thousands of pounds out of pocket. ( If my memory serves )..